Re: Subtracting and Comparing Two Dates

# Always use gmtime and timegm when
# dealing with dates without times.

use Time::Local qw( timegm );

# Replace with your input.
my $then_date_str = 'YYYYMMDD';

my $then_date = do {
   my ($y, $m, $d) = $then_date_str =~ /^(.{4})(.{2})(.{2})\z/;
   $m--;
   timegm(0, 0, 0, $d, $m, $y)
};

my $now_date = do {
   my ($y, $m, $d) = (localtime())[5,4,3];
   timegm(0, 0, 0, $d, $m, $y)
};

my $diff = $now_date - $then_date;
my $diff_days = int($diff / (24*60*60));

if    ($diff_days <  -1) { printf("%d days ago\n", -$diff_days); }
elsif ($diff_days == -1) { print("yesterday\n"); }
elsif ($diff_days ==  1) { print("tomorrow\n"); }
elsif ($diff_days >   1) { printf("%d days from now\n", $diff_days); }
else                     { print("today\n"); }
[download]

Notes:

Time::Local is a core module.
I advise against this method. Use Date::Calc.
It only supports dates time can return.

Update: Oops, I was subtracting from $m twice. Fixed.

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Re^2: Subtracting and Comparing Two Dates by BaldPenguin (Friar) on Jan 08, 2007 at 23:03 UTC
For my own clarification, what benefits are there to using Time::Local instead of POSIX. The functionality seems to be the same. Is implemetation different? Or is it just a preference thing? Don WHITEPAGES.COM \| INC Everything I've learned in life can be summed up in a small perl script!	[reply]
Re^3: Subtracting and Comparing Two Dates by ikegami (Patriarch) on Jan 08, 2007 at 23:11 UTC
I don't see anything in POSIX similar to Time::Local's `timegm`. To which POSIX function were you refering?	[reply] [d/l]
Re^4: Subtracting and Comparing Two Dates by BaldPenguin (Friar) on Jan 08, 2007 at 23:18 UTC
timegm() in Time::Local == gmtime() in POSIX After looking it looks like Time::Local is a Pure Perl interface to the Perl localtime objects where POSIX is an XS interface to the system libraries. Don WHITEPAGES.COM \| INC Everything I've learned in life can be summed up in a small perl script!	[reply]
Re^5: Subtracting and Comparing Two Dates by ikegami (Patriarch) on Jan 09, 2007 at 01:05 UTC
Re^5: Subtracting and Comparing Two Dates by jettero (Monsignor) on Jan 08, 2007 at 23:35 UTC
Re^2: Subtracting and Comparing Two Dates by mindful07 (Initiate) on Jan 11, 2007 at 22:29 UTC
Right now I do not have Date::Calc installed and I'm trying to figure out how I can get the value in days of two dates. Here is my code to give you an idea of what I'm trying to accomplish. If I somehow can get date::calc installed could I just then do $diff_in_days = Delta_days($sysdate, $installed_date)? Also in the event I can't install date::Calc can you please give a suggestion of how else to accomplish this? use POSIX qw(strftime); use Time::Local; #use Date::Calc qw(:all); #use time::Piece; #use Date::Calc qw(Delta_Days); sub give_warning { my($carrier) = @_; my($installed_date); my($max_days) = 15; $installed_date = get_value($carrier ."_DAYS", $trn_info, '') ; printf("Value of Carrier Days is $installed_date \n"); if ($installed_date ne "" ) { my $sysdate = decode_date ('SYSDATE','CCYYMMDD'); printf("Todays date is $sysdate \n"); my $diff_in_days = $sysdate - $installed_date ; print "Difference in days: $diff_in_days\n"; if $result > $max_days # give error and return { &print_error ("New Installation is required."); return 1; } elsif $result <= $max_days # give warning and return { &print_warning ("New Installation is required."); return 0; } } else { return 0; } } [download]	[reply] [d/l]
Re^3: Subtracting and Comparing Two Dates by ikegami (Patriarch) on Jan 11, 2007 at 22:45 UTC
Why do you want me to look at this? The code in the post to which you replied does exactly what you want.	[reply]
Re^4: Subtracting and Comparing Two Dates by mindful07 (Initiate) on Jan 11, 2007 at 23:34 UTC
I apologize. I've tried so many suggestions and I thought when I tried to use local:time(timegm) it had given me an error when i tried to include it. It works just fine. Thanks again for your help!	[reply]